| (19) |
 |
|
(11) |
EP 0 851 005 A3 |
| (12) |
EUROPEAN PATENT APPLICATION |
| (88) |
Date of publication A3: |
|
25.11.1998 Bulletin 1998/48 |
| (43) |
Date of publication A2: |
|
01.07.1998 Bulletin 1998/27 |
| (22) |
Date of filing: 19.12.1997 |
|
|
| (84) |
Designated Contracting States: |
|
AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE |
|
Designated Extension States: |
|
AL LT LV MK RO SI |
| (30) |
Priority: |
20.12.1996 JP 342226/96
02.06.1997 JP 144058/97
05.12.1997 JP 335470/97
|
| (71) |
Applicants: |
|
- SEIKO EPSON CORPORATION
Shinjuku-ku
Tokyo (JP)
- Mikuni Color Ltd.
Himeiji-shi,
Hyogo-ken (JP)
|
|
| (72) |
Inventors: |
|
- Nakamura, Hiroto
Suwa-shi,
Nagano (JP)
- Komatsu, Hidehiko
Suwa-shi,
Nagano (JP)
- Tsukahara, Michinari
Suwa-shi,
Nagano (JP)
- Yamazaki, Hideo
Suwa-shi,
Nagano (JP)
- Waki, Minoru,
C/o Mikuni Color Ltd.
Himeji-shi,
Hyogo (JP)
- Okamoto, Naoki,
C/o Mikuni Color Ltd.
Himeji-shi,
Hyogo (JP)
- Adachi, Kazumi,
C/o Mikuni Color Ltd.
Himeji-shi,
Hyogo (JP)
|
| (74) |
Representative: Hasenrader, Hubert et al |
|
Cabinet Beau de Loménie
158, rue de l'Université
75340 Paris Cédex 07
75340 Paris Cédex 07 (FR) |
|
| |
|
| (54) |
Agglomerated pigment, process for producing the same, aqueous pigment dispersion,
and water-based ink composition |
(57) An agglomerated pigment comprises (1) an organic pigment compound, (2) either a sulfonated
organic pigment compound obtained by incorporating at least one sulfonic group into
the organic pigment compound or a sulfonated organic pigment derivative obtained by
incorporating at least one sulfonic group into a derivative of the organic pigment
compound, (3) univalent inorganic counter ions bonded to sulfonic groups of component
(2), and (4) bivalent or higher inorganic counter ions which are bonded to sulfonic
groups of component (2) and each has an at least univalent positive charge, the surface
of the agglomerated organic pigment as a whole being positively charged. An aqueous
pigment dispersion and a water-based ink composition both having excellent storage
stability, an agglomerated pigment for use as a raw material for the dispersion, and
a process for producing the pigment are provided.